Partitioning of a communications network

ABSTRACT

This invention relates to the partitioning of a communications network. The idea of the invention is to divide the logical connections of a communication network into several partitions, each partition representing a certain type of transmission traffic, such as access or regional traffic. The partitioning is based on simple criteria: capacity of an endpoint of a logical connection, representing a node; distance between a pair of endpoints, and traffic category representing the stability of the traffic. By using the partitioning, it is possible to separate a certain type of traffic (a certain type of logical connections) from the whole traffic picture of the network

FIELD OF THE INVENTION

[0001] This invention relates to the partitioning of a communicationsnetwork.

BACKGROUND OF THE INVENTION

[0002] A network planning process involves several competing targets.The network should be compact and flexible to operate, and easy toexpand. The network capacity and investments are planned to follow theexpected transmission needs and the actual sales of transport services.There exist many alternative architectures to realize the network.

[0003] The first network investment of the operator must be reasonablein size, but big enough to ensure credibility and the near future growthof the network. In other words, a certain minimum coverage of thenetwork is needed, and the growth of the network must be securedtechnically and economically at the same time.

[0004] Usually, these matters mean the need of building the networkgradually, to add and modify network nodes and transmission lines. Thechanges in the network nodes can be frequent, which means repetitiveadditions of equipment, changes in the use of existing equipment, theincrease of capacity, and adding more line interfaces. Usually, thechanges also mean changes in synchronization paths and in networkmanagement channels.

[0005] Problems arise when the required changes are not possible to doin the existing nodes, or they can be done, but the existing resourcesare not used efficiently. For example, more capacity is needed in a nodeand thus new equipment must be added into the node, but there is no freespace inside the rack. Or the added transmission capacity is for lowcapacity access traffic, but the node is capable of handling highcapacity regional traffic, when the node is too big and expensive tohandle just access traffic. In other words, the changes and the existingequipment must match with each other. Frequent changes in the futureshould be taken into account. The traffic in the network can be high orlow capacity traffic, and dynamic or stable traffic in relation to thetime period. The objective of the invention is to alleviate theabove-mentioned drawbacks. This is achieved in a way described in theclaims.

SUMMARY OF THE INVENTION

[0006] The idea of the invention is to divide the logical connections ofa communication network into several partitions, each partitionrepresenting a certain type of transmission traffic, such as access orregional traffic. The partitioning is based on simple criteria: capacityof an endpoint of a logical connection, representing a node; distancebetween a pair of endpoints, and traffic category representing thestability of the traffic. By using the partitioning, it is possible toseparate a certain type of traffic (a certain type of logicalconnections) from the whole traffic picture of the network. Thepartition offers a useful way for the designer of the network to decidewhat equipment is placed in each node, taking into account the costs andfuture growth.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the following the invention is described in more detail bymeans of FIGS. 1-2 in the attached drawings where,

[0008]FIG. 1 illustrates different types of transmission traffic,

[0009]FIG. 2 illustrates the inventive method as a flow chart.

DETAILED DESCRIPTION OF THE INVENTION

[0010]FIG. 1 illustrates what different types of transmission trafficcan be found in a communication network. The vertical axis shows thecapacity demand of the traffic, and the horizontal axis shows the needof rerouting in a large physical area, i.e. the stability of thetraffic. P1 represents large capacity traffic, such as optical trunktraffic. Usually the optical traffic between endpoints in the backbonetrunks of a communications network is stable, i.e. there is no need forrerouting traffic in a large physical area in relation to a certainperiod. P2 represents traffic in a regional level (such as a city area).Capacity needs are not as high as P1 has, but the traffic is moredynamic. P3 represents low capacity traffic, such as leased cellularnetwork traffic for small businesses. In this case the need forrerouting is very high.

[0011] The starting point for the whole network plan is all desiredlogical connections (traffic requirements) that specify the endpoints ofthe logical connections, capacity of the endpoints, and the descriptivecategory (traffic type) of the logical connections (e.g. mobile phonetraffic, interswitch traffic, data, leased line). The goal of thepartition process is to divide the logical connections into separatepartitions. The criteria that define a good partition are:

[0012] 1. Equipment capacity is efficiently used. Not too low to get agood utilization percentage, and not too high to have some room forgrowth. The growth estimates are different for different types oftraffic.

[0013] 2. The length of routes are as short as possible. This is becauselonger routes require more intermediate equipment and thus increase thecost. Long routes are also more likely to be broken by some accident.

[0014] 3. It is useful to separate the traffic with a certain stabilityfrom the traffic with other stabilities.

[0015] Since the above criteria require that a detailed plan for thepartitioning is available, it is impossible to use those criteriadirectly in the partitioning process. Therefore the following simplercriteria must be used:

[0016] 1. The capacity of the endpoints of a logical connection in asingle partition is between given limits.

[0017] 2. The distances between pairs of endpoints in a single partitionare between given limits.

[0018] 3. A single partition contain a specific category of logicalconnections (traffic type). The category can be used to deduce howlikely it is that the endpoints of the connection are going to change.E.g. traffic between PSTN switches in large cities is very stable andhigh capacity while leased line traffic used e.g. by a group of shops islikely to change.

[0019] Special software can do the partition for separating the desiredtraffic from the logical connections. The designer chooses the capacityand distance limits, and the right category. By using the partition, itis easier for the designer to plan the network, taking into accountdifferent traffic types, equipment costs, and future growth.

[0020]FIG. 2 illustrates the invention as a flow chart. The inputinformation is the logical connections of the network. The informationcontains all traffic demands for all kinds of traffic types. Thesoftware offers a possibility to select limits (21) for finding certainlogical connections from all the logical connections. The limits arebased on the above-mentioned simple criteria. After selecting thelimits, the software forms two partitions (22): the primary partitionwhich contains the logical connections inside the selected limits, i.e.the partition which is desired to be formed first, and the secondarypartition, which is the rest of the logical connection outside theselected limits. The software shows (23) graphically the primarypartition to the designer, who can decide if the primary partition isacceptable. If the designer wants to change the partition made, it canbe repeated (24). If the designer is satisfied with the partition, a newpartition from the secondary partition can be formed (25). The samesteps (21,22,23,24) are done for the new partition: selecting limits,forming two partitions, showing the primary desired partition (thelatest one) graphically, and changing the partition, if needed. Thepartition of the secondary partition can be repeated until all desiredtraffic types have been separated into the separate partitions. The lastpartition is the latest secondary partition, which is shown graphically(26) finally. The minimum number of partitions is two when the secondarypartition is shown graphically after the primary partition is accepted.In this case new partitions from the secondary partition (25) are notrequired.

[0021] After the partition process, the designer can route and equip thenetwork nodes separately in each partition. The partitions are connectedtogether for getting the whole picture of the network. The inventivesoftware and the method offer an effective way to take into accountdifferent requirements of network planning: future growth,cost-effectiveness, reliability matters, and so on. Although, theinvention is described in a way that three parameters (capacity,distance, and traffic type) are taken into account in the partitioning,it is possible to use another number of parameters, such as only twoparameters: capacity and traffic type. Or it is possible to use morethan three parameters for forming a desired multidimensional domain forthe limits using in the partitioning. The invention is a method that canbe used in many implementations and network solutions, in the scope ofthe inventive idea.

1. A network planning method for partitioning a communication network, characterized in that the method comprises the steps of: describing logical connections in the network in a domain comprising at least two dimensions, the first dimension being for describing the capacity of endpoints of said logical connections, and the second dimension being for describing the re-routing needs of said logical connections, selecting a value range for each of the dimensions, searching for logical connections which are within the selected value ranges in the domain, and forming a primary partition from the logical connections found.
 2. A method according to claim 1, characterized in that the method further comprises the step of representing the primary partition graphically.
 3. A method according to claim 1, characterized in that the method further comprises the step of forming a secondary partition from logical connections which fail to belong to the primary partition.
 4. A method according to claim 1, characterized in that the method further comprises the step of changing the partition made.
 5. A method according to claim 3, characterized in that the method further comprises the step of forming a new partition from the secondary partition, whereby logical connections not belonging to the new partition form the latest secondary partition.
 6. A method according to claim 5, characterized in that the method further comprises repeating the forming of a new partition from the logical connections of the latest secondary partition.
 7. A method according to claim 3 or 6, characterized in that the method further comprises showing the secondary partition graphically.
 8. A method according to claim 1, characterized in that the domain comprises a third dimension that describes the distance between the endpoints of said logical connections. 